Does anyone have a recommendation for affordable field strength meters?? Something under $150 preferably (if that exists).

I am using a magnetic loop to transmit data and I am wanting to double check the actual readings against FCC regulations while it is in use to avoid any risk to pets/people in the house.

Many thanks,

John - W3JED

And, I am transmitting in the 7 kHz to 19 kHz range.

I am curious, which FCC regulation can authorize transmitting in that range?

73, Mike AF7KR

My apologies - I meant to say 7000 kHz to 19000 kHz, basically 17 meter through 40 meter bands.

开云体育

The SDRplay RSP has a very accurate signal level meter, a fairly accurate 50 ohm input impedance, requires a fairly modest laptop and will allow one to make near lab grade measurements on the cheap.

?

The problem with trying to make actual RF level readings from an antenna is the antenna factor is critical.

By that I mean real free space RF level measurements require calibrated antenna.

While they exist they are pricy.

Check out:

https://www.theemcshop.com/loop-antennas/3362-ala30m-active-loop-antenna-for-magnetic-field-testing.html?utm_campaign=2.+Test&utm_source=adwords&utm_medium=ppc&hsa_acc=2517515894&hsa_cam=643679951&hsa_grp=29338994341&hsa_ad=109901808181&hsa_src=g&hsa_tgt=pla-55733401733&hsa_net=adwords&hsa_ver=3

For a cool $3,079.00.

I've been dealing with home grown EMI trying to come up with accurate signal levels.

I can achieve repeatable measurements but they are hardly lab grade.

Another problem with trying to measuring HF RF is the levels vary unpredictably in a room.

I use a PA0RDT antenna, RSP1a, HP laptop and it is amazing how moving the test rig a few feet will change the levels.Think of the shadows on the bottom of a swimming pool. Areas of and dark.
Look up near and far field.

?

Good luck.

Jeff

Take a look at:

https://www.fcc.gov/general/oet-bulletins-line

Go down to OET Bulletin No. 65 (August 1997)

On March 8, 2023, there are 3 pdfs that offer some guidance.

On Wed, Mar 8, 2023 at 02:54 PM, W0LEV wrote:

A field strength meter is typically uncalibrated.

True. I picked up a somewhat calibrated field strength meter meant to be used for TV antennas. Of course, there is no antenna that comes with it, but it'll tell you the microvolts at the coax terminal. It has to be tuned to an individual channel, so only good over the old TV bands. I've been trying to figure out what to do with it.
?
--
Steve Greenfield AE7HD

John,
If, when you're transmitting the dog isn't rubbing his hind end across the carpet and your skin doesn't feel hot you should be good to go.

Sounds like a fun project!
Carl